I'm a gog.com user and sadly I've purchased the game directly here without thinking about gog.com account.
There's a way to receive a gog.com code like the steam key you're giving on request?
Thanks for your answer, when you can give one to me.

The game is truly great. The mechanics are smart and intuitive, but it's brain cracking for get new solutions for everyday problems. :D The best phrase I can tell is " the last 10 year best spent money". Sorry if not perfect, because I'm not so good with english, but compliments are a must...